Gdyby autobus nie przyjechał, musiałbym iść pieszo do pracy.

If the bus didn’t arrive, I would have to walk to work.

Breakdown of Gdyby autobus nie przyjechał, musiałbym iść pieszo do pracy.

• ja: I
• iść: to go
• do: to
• nie: not

Questions & Answers about Gdyby autobus nie przyjechał, musiałbym iść pieszo do pracy.

What does gdyby mean here?

Gdyby introduces a hypothetical condition. In this sentence, it means if in the sense of if the bus didn’t arrive / if the bus were not to arrive.

It is used for unreal or imagined situations. That is different from a more neutral condition with jeśli or jeżeli, which often corresponds to ordinary if in English.

So the structure is:

• Gdyby autobus nie przyjechał = If the bus didn’t arrive
• musiałbym iść pieszo do pracy = I would have to walk to work

Why is przyjechał a past-tense-looking form if the sentence is hypothetical, not necessarily about the past?

This is one of the most common things that confuses English speakers.

After gdyby, Polish normally uses a past form of the verb, even when the meaning is hypothetical rather than truly past. So:

• gdyby ... przyjechał
  literally looks like if ... arrived / had arrived
• but in meaning it often works like English if ... didn’t come / were not to come

So Polish forms unreal conditions differently from English. The form is past, but the meaning is conditional/hypothetical.

Also, przyjechał agrees with autobus, which is masculine singular, so the masculine singular form is used.

Why is it przyjechał and not przyjeżdżał?